I think you're right, Carl. But doesn't the pushbutton door handle have an attachment screw from behind the weatherstrip as well?
Here's the best pic I have of the upper portion of my '51 doors. One of the lower wing vent tab holes has a captive nut and the other uses a nut and bolt. Those holes looked too small in the OP's picture, but they are there for the wing vent attachment. There's also a reinforcement just forward of the division bar where the roll-up window goes.
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Last edited by klhansen; 10/09/2021 10:53 PM.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.